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June 12, 2012

Carbon-Metal Carbon Capture

by editor

Brett Smith for redOrbit.com

Cutting edge carbon capture technology is having quite the year so far as UK scientists said they have developed a "metal-organic framework" that works like a sponge, absorbing carbon dioxide from high pressure emissions.

This latest breakthrough in clean energy technology, called NOTT-202, absorbs CO2 from the atmosphere by soaking in pressurized gasses and releasing these gases under lowered pressure while retaining the greenhouse gas, according to a report in the latest online edition of Nature Materials.

"Increasing the selectivity for CO2 in the presence of gaseous mixtures represents a major challenge if these systems are to find practical applications under dynamic conditions," the authors wrote.

Metal-organic frameworks have been among the leading candidates for trapping emissions for a number of years. These materials are comprised of a metallic element at their core, surrounded by a matrix of longer, carbon-containing strands.

These complex molecules can be made to join together in frameworks that leave gaps suitable for capturing gases. Until now, such molecular frameworks have been good primarily at collecting any gas passing through them, while those that were selective for CO2 have not been especially efficient at capturing and retaining the gas.

A discovery at the universities of Nottingham and Newcastle, where scientists discovered a chemical system that seemed to solve this problem of selectively storing a significant amount of CO2 created the spark that resulted in this new discovery.

To be sure of what these scientists have discovered, they collaborated with a team at the Diamond Light Source in Oxfordshire and the Science and Technology Facilities Council's Daresbury Laboratory to get a microscopic look at what they had created.

Using various X-ray techniques and detailed computer models, the researchers found that NOTT-202 is made up of two different frameworks that fit together in a weird way, leaving "nanopore" gaps that are uniquely suited to gathering up CO2. This two-part structure, the researchers claim, is an entirely new class of porous material.

As a result, new research into just how similarly paired frameworks can be created may help researchers find a range of specialized materials suited to soaking up specific gases.

This latest development comes on the heels of studies published earlier this month that showed a marked jump in the levels of carbon dioxide.

Several arctic monitoring stations are measuring more than 400 parts per million (ppm) of the heat-trapping gas in the atmosphere this spring, compared with the 350 ppm that many scientists say is the highest safe level for carbon dioxide.

Carbon dioxide is the chief and most effective greenhouse gas and stays in the atmosphere for approximately 100 years. According to climate scientists, the 2011 emission levels set the world on a path toward a dangerous 2 degrees Celsius rise in average temperature. The result of this increase would be a water and food scarcity in certain areas along with increased levels of disease.

The IEA said it's becoming unlikely that the world can achieve the European goal of limiting global warming to just 2 degrees based on increasing pollution and emission levels.